Here are the results for the given function $V(r) = \frac{4}{3} \pi r^3$:

(a) $V(2) = 10.67\pi$

(b) $V\left(\sqrt{\frac{3}{2}}\right) = 2.45\pi$

(c) $V(3r) = 36\pi r^3$

If you have any questions or need further details, feel free to ask!

Related Questions:

1. How is the formula for the volume of a sphere derived?
2. What happens to the volume when you triple the radius?
3. How can you simplify the expression $V(kr)$ in general terms?
4. What is the significance of $\pi$ in geometric problems like this?
5. How can the volume formula be applied to real-world objects?

Tip: Always simplify expressions before substituting values to avoid errors in more complex calculations!